1. Technical Field of the Invention
The present invention concerns devices intended to fit around a wheel rim, such as safety supports for vehicle tires, sensors, or automatic inflation systems and, more particularly, to the connection between such devices and the rims around which they are mounted.
2. The Related Art
The main function of tire safety supports is to support the load in the event that the tire suffers a major pressure loss. When tires are inflated normally, the safety supports must not have any adverse effect on the dynamic properties of the tire. In particular, they must remain well centered around the rim; that is to say, the rotational axes of the safety support and of the rim must remain one and the same to avoid any out-of-balance effect, and this, whatever the temperature of the support and the vehicle's rolling speed. It must also be possible to mount the safety supports around the wheel rims of vehicles and take them off again in an easy way, i.e., using limited forces which make it possible to fit and remove them by hand.
U.S. Pat. No. 5,690,762 discloses a safety support made of an elastic material designed to be fitted on the wheel rim of a touring vehicle, the rim being of the usual, drop-center type. This support comprises a body with a crown designed to come into contact with the crown of the tire if the latter should lose pressure, and a base designed to come into contact with the rim. This support also comprises annular reinforcement elements oriented circumferentially and essentially inextensible, whose diameter is slightly larger than the diameter of the rim hooks for which the support is provided. The base consists of two annular zones whose inside diameter in the free state is smaller than that of the parts of the rim upon which they are to rest: the compression of these annular zones therefore ensures good centering of the support on the rim. The function of the annular reinforcing elements is, in particular, to prevent the annular zones of the base from extending under the action of centrifugal forces at high speed until contact with the rim is lost.
When a safety support is intended to be fitted to a two-part rim or a rim having a bearing surface for a support whose diameter is larger than that of one of the rim hooks as shown in FIG. 1, the annular reinforcing elements can be arranged in the base. This is so in the case of the support disclosed by U.S. Pat. No. 5,891,279. Such a position of the annular reinforcing elements facilitates the construction of the support.
For such a support, bearing in mind the manufacturing tolerances of the rim and the support itself, it is no longer possible to arrange annular zones radially on the inside whose compression will ensure good centering around the rim regardless of the speed while also ensuring easy fitting and removal.